| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens of two-group constitution which is lower in cost, smaller in size and lighter in weight. SOLUTION: This zoom lens comprises, successively from an object side, a first lens group having positive refracting power and a second lens group having negative refracting power and varies the power by changing the spacing between both. The first lens group consists, successively from an object side, of three lens elements; the first lens, the second lens and the third lens and their image side diaphragm. The first lens is a plastic lens, the second lens has negative refracting power and the third lens has positive refracting power and the second lens group consists of two lens elements and is a fourth lens and a fifth lens having negative refracting power toward the image plane side. The zoom lens satisfies the following conditions: 1.50<=n3<=1.90, 1.50<=n5<=1.90, where n3: the refractive index of the third lens counted from the object side, n5: the refractive index of the fifth lens counted from the object side.
|
